The disclosure relates to substrates exhibiting anti-glare properties and more particularly to substrates exhibiting uniform textured surface and low sparkle. Methods for making such substrates are also disclosed.
Advances in consumer electronic technology has necessitated improvements in various cover substrate properties. One such area for improvement is anti-glare surfaces for consumer electronic devices such as smart (mobile) phones, tablets, electronic readers, displays and TVs.
Reduction of the specular reflection is often a desired property in touch sensitive electronic devices, electronic ink readers, interactive whiteboards, and other portable LCD panels, especially when used in certain light conditions. Cover substrates exhibiting such properties can be realized by coating with anti-reflection layers or creating textures on the surface (thus forming an anti-glare surface). The surface texture reduces the reflection light through the random scattering of the reflected light and leads to a blurred reflective image.
For consumer electronic applications, known anti-glare surfaces can exhibit sparkle (or a grainy appearance) at low transmittance haze levels (e.g., about 10% or less). Display “sparkle” is a phenomenon that can occur when anti-glare or light scattering surfaces are incorporated into a display system. Sparkle is associated with a very fine grainy appearance that can appear to have a shift in the pattern of the grains with changing viewing angle of the display. This type of sparkle is observed when pixelated displays such as LCDs are viewed through an antiglare surface. Such sparkle is of a different type and origin from “sparkle” or “speckle” that has been observed and characterized in projection or laser systems
As displays exhibit higher definition and more pixels are assembled at higher densities, the reduction of sparkle becomes more important. Known anti-glare technologies, such as anti-glare film lamination, sand blasting, sol-gel coating, tend to produce significant sparkle. Accordingly, there is a need for anti-glare surfaces that exhibit low sparkle, while still exhibiting low DOI and low transmission haze.